Cache Testing
Reese,
With both Speedway and Speedcache+, the cache for motion video playback
needs to be at least as big as the largest clip to be played. Otherwise, no
effective caching occurs. In the case of Speedway, even those who don't
have much in the way of extra RAM can usually allocate enough hard disk
space for the cache to allow movie clips to be played from the cache. On my
particular system, the HD is fast enough so that there is no significant
performance difference with Speedway between using the RAM drive and using
the disk cache. The clip can still be pumped to the display fast enough so
that the display doesn't have to wait for the next block of data. This
might be a lot different on a 486/50 using local bus video, in which case,
using a RAM drive cache might be the best.
In contrast, Speedcache+ does all of its caching directly from RAM,
without the file I/O overhead of Speedway, which probably accounts for the
somewhat smoother performance. Also, with Speedcache+, during the CD
access, the data is being sent directly to the display while the cache is
being loaded, so there is no wait to see the clip, even though it may be
jerky at this point. Subsequent replays of the same clip are from the cache
with no CD access at all. This is what happens with Speedway also, except
that playing is from the cache only and we have to wait for the CD read to
finish before seeing the video. Apparently the upgrades you mentioned will
improve this and I look forward to testing them as well.
Regards,
Tom